JP6327962B2 - Reflector antenna device - Google Patents

Description

  The present invention relates to an antenna device, and more particularly to a reflector antenna device.

  2. Description of the Related Art Conventionally, a reflector antenna having a primary radiator that radiates electromagnetic waves and a reflector that is disposed opposite to the primary radiator and reflects electromagnetic waves has been used. As the primary radiator of the reflector antenna, a horn antenna having an inverted frustum-shaped horn is used (see, for example, Patent Document 1 and Patent Document 2).

  The horn antenna of Patent Document 1 has a pattern of electromagnetic waves radiated from an opening (hereinafter referred to as “radiation pattern”) by providing notches at four corners of the inner surface of a horn having a quadrangular cross section (so-called “pyramidal horn”). ) Is brought closer to an axisymmetric pattern with respect to the tube axis of the horn to improve axial symmetry. The horn antenna of Patent Document 2 improves the axial symmetry by providing corrugated irregularities at the four corners of the inner surface of the pyramid horn, bringing the radiation pattern closer to the axially symmetric pattern with respect to the tube axis of the horn. Yes.

JP-A-55-145402 JP 56-165403 A

  A reflecting mirror antenna mounted on an artificial satellite uses a reflecting mirror having a mirror surface with a rectangular outer shape in order to satisfy the conditions for mounting on an artificial satellite and to maximize the aperture area of the antenna. In order to irradiate electromagnetic waves efficiently to this reflector, the distribution of electromagnetic waves on the mirror surface of the reflector (hereinafter referred to as “reflector aperture distribution”) is made close to a uniform rectangular distribution, and the primary radiator It is important to reduce electromagnetic waves radiated toward the outside of the reflector, so-called “spillover”.

  A primary radiator using a horn having a circular cross section (so-called “conical horn”) has a radiation pattern that is axisymmetric with respect to the tube axis of the horn, and the distribution of electromagnetic waves in the opening of the primary radiator (hereinafter “ "Radio aperture distribution") is a circular distribution. That is, although spillover can be suppressed, there is a problem that the reflection mirror aperture distribution does not become a rectangular distribution, and the intensity of the electromagnetic wave amplitude distribution becomes weak at the four corners of the mirror surface.

  A primary radiator using a normal pyramid horn has a radiator aperture distribution close to a rectangular shape, but unnecessary electromagnetic waves are radiated along a plane along the electric field of the electromagnetic wave (so-called “E plane”) at the opening. As a result, a so-called “side lobe” is generated in the radiation pattern. For this reason, there is a problem that spillover becomes large.

  The primary radiator using the pyramid horn of Patent Document 1 improves the axial symmetry of the radiation pattern by providing notches at the four corners of the inner surface. However, this notch has a problem that the radiator aperture distribution does not become a rectangular distribution. Moreover, the primary radiator using the pyramid horn of Patent Document 2 improves the axial symmetry of the radiation pattern by providing corrugated irregularities at the four corners of the inner surface. However, there is a problem that the radiator aperture distribution does not become a rectangular distribution due to the unevenness.

  The present invention has been made in order to solve the above-described problems, and a reflector antenna device capable of making the reflector aperture distribution a uniform rectangular distribution and reducing spillover. The purpose is to provide.

The reflector antenna device of the present invention includes a mirror surface having a rectangular outer shape and a primary radiator disposed so as to face the mirror surface, and reflects the electromagnetic wave radiated from the primary radiator on the mirror surface. The primary radiator has a rectangular cavity at the opening of the inverted frustum-shaped horn, and two auxiliary cavities adjacent to the rectangular cavity so as to be symmetrical in a plane parallel to the electromagnetic field. A radiator aperture that is a Fourier transform of the reflector aperture distribution on the mirror surface so that the amplitude and phase of the electromagnetic wave are uniformly distributed on the mirror surface by forming a coupling portion between the square cavity and auxiliary cavity and the horn. The distribution is set.

  The reflector antenna device of the present invention can make the reflector aperture distribution a uniform rectangular distribution and reduce spillover.

It is explanatory drawing which shows the structure of the reflective mirror antenna apparatus of Embodiment 1 of this invention. It is explanatory drawing which shows amplitude distribution of the opening part of the primary radiator of Embodiment 1 of this invention. It is explanatory drawing which shows the phase distribution of the opening part of the primary radiator of Embodiment 1 of this invention. It is explanatory drawing which shows the structure of the primary radiator of Embodiment 2 of this invention. It is explanatory drawing which shows the structure of the reflective mirror antenna apparatus of Embodiment 2 of this invention. It is explanatory drawing which shows the structure of the primary radiator of Embodiment 3 of this invention. It is explanatory drawing which shows the structure of the reflective mirror antenna apparatus of Embodiment 3 of this invention. It is explanatory drawing which shows the structure of the primary radiator of Embodiment 4 of this invention. It is explanatory drawing which shows the structure of the reflective mirror antenna apparatus of Embodiment 4 of this invention. It is explanatory drawing which shows the structure of the primary radiator of Embodiment 5 of this invention. It is explanatory drawing which shows the structure of the reflective mirror antenna apparatus of Embodiment 5 of this invention.

Embodiment 1 FIG.
With reference to FIGS. 1-3, the reflector antenna apparatus of Embodiment 1 of this invention is demonstrated.
In the figure, 1 is a primary radiator. The primary radiator 1 is constituted by, for example, an array antenna in which a plurality of antenna elements having inverted frustum-shaped horns are arranged at a predetermined interval. The primary radiator 1 radiates electromagnetic waves from the opening 2.

  A reflecting mirror 3 is arranged so as to face the opening 2 of the primary radiator 1. The reflection mirror 3 has a mirror surface 4 having a rectangular outer shape, and reflects the electromagnetic wave irradiated from the opening 2 of the primary radiator 1 in a predetermined direction. The primary radiator 1 and the reflecting mirror 3 constitute a reflecting mirror antenna device 100.

  Here, the distribution of electromagnetic waves (radiator aperture distribution) in the opening 2 of the ideal primary radiator 1 is a function that makes the amplitude and phase of the electromagnetic waves uniform on the rectangular mirror surface 4. For this reason, the radiator aperture distribution of the primary radiator 1 is a so-called “sinc function” distribution that is a Fourier transform of the electromagnetic wave distribution (reflector mirror aperture distribution) on the mirror surface 4 of the reflector 3. That is, the amplitude distribution of the electromagnetic wave in the opening 2 of the primary radiator 1 is set to a sinc function distribution. Further, the phase distribution of the electromagnetic wave in the opening 2 of the primary radiator 1 is set to a distribution having a substantially uniform rectangular shape.

  FIG. 2 shows the amplitude distribution of the electromagnetic wave in the opening 2 of the primary radiator 1. In the drawing, a rectangle I surrounded by an A-B-C-D line indicates a rectangular region corresponding to the mirror surface 4, that is, a region where the radiated electromagnetic wave is irradiated on the mirror surface 4. As shown in FIG. 2, the amplitude distribution inside the rectangle I has the largest amplitude at the central portion O of about −20 decibels (dB), and gradually increases from the central portion O toward the ABCD line ( In other words, the amplitude is small (in the form of a sinc function). In addition, outside the four sides of the rectangle I, a region II whose amplitude is smaller than the central portion O by about 15 dB is formed.

  FIG. 3 shows the phase distribution of the electromagnetic wave in the opening 2 of the primary radiator 1. In the drawing, a rectangle I surrounded by an A-B-C-D line indicates a rectangular area corresponding to the mirror surface 4. As shown in FIG. 3, the phase distribution of the region III inside the rectangle I is substantially uniform. Further, the phase of the region IV outside the four sides of the rectangle I is substantially opposite to the phase of the region III.

  In the primary radiator 1, the distance between the antenna elements is sufficiently small. Further, the amplitude distribution of the opening of each antenna element is set to a distribution obtained by sampling the distribution shown in FIG. 2, and the phase distribution of the opening of each antenna element is set to a distribution obtained by sampling the distribution shown in FIG. Has been. Thus, using the primary radiator 1 having a finite aperture diameter, the radiator aperture distribution of the primary radiator 1 is shown in FIGS. 2 and 3 in the same manner as an ideal primary radiator having an infinite aperture diameter. Can be distributed.

Next, the operation of the reflector antenna device 100 will be described with reference to FIGS.
First, the primary radiator 1 radiates electromagnetic waves from the opening 2. Next, the reflecting mirror 3 reflects the electromagnetic wave applied to the mirror surface 4 in a predetermined direction.

  At this time, since the amplitude distribution of the electromagnetic wave in the opening 2 of the primary radiator 1 is the distribution shown in FIG. 2, the amplitude distribution of the electromagnetic wave on the mirror surface 4 is a rectangular uniform distribution. Moreover, since the phase distribution of the electromagnetic wave of the opening part 2 of the primary radiator 1 is distribution shown in FIG. 3, the phase distribution of the electromagnetic wave on the mirror surface 4 becomes a rectangular uniform distribution. That is, both the amplitude and phase of the electromagnetic wave are uniform on the rectangular mirror surface 4, and spillover can be suppressed.

  The reflector antenna device 100 operates in the same manner when receiving electromagnetic waves according to the so-called “antenna reversibility theorem”. That is, the electromagnetic wave irradiated with a uniform distribution on the rectangular mirror surface 4 is reflected toward the primary radiator 1. At this time, the radiator aperture distribution of the primary radiator 1 is the distribution shown in FIGS.

  As described above, in the reflector antenna device 100 according to the first embodiment, the radiator aperture distribution of the primary radiator 1 is set to the distributions shown in FIGS. The distribution can be a uniform rectangular distribution, and spillover can be suppressed. As a result, the electromagnetic wave can be efficiently irradiated from the primary radiator 1 to the rectangular mirror surface 4.

Embodiment 2. FIG.
A reflector antenna apparatus using a conical horn as a primary radiator will be described with reference to FIGS. 4 and 5. In addition, the same code | symbol is attached | subjected to the structural member similar to the reflector antenna apparatus 100 of Embodiment 1 shown in FIG. 1, and description is abbreviate | omitted.

  In the figure, 5 is a conical horn. The horn opening 6 of the conical horn 5 is provided with a main cavity (square cavity) 7 having a square cross section. The main cavity 7 has a hollow portion that communicates with the horn opening 6, and is formed with a coupling portion 8 including a coupling hole that electromagnetically couples with the conical horn 5.

  Adjacent to the side of the main cavity 7, two auxiliary cavities 9 and 10 having a square cross section are provided. The auxiliary cavities 9 and 10 have a hollow portion that communicates with the horn opening 6, and coupling portions 11 and 12 that are coupling holes that are electromagnetically coupled to the conical horn 5 are formed. A primary radiator opening is constituted by the main cavity 7 and the auxiliary cavities 9 and 10.

  The length L of the main cavity 7 along the tube axis direction of the conical horn 5 is equivalent to a quarter wavelength of the radiated electromagnetic wave. The two auxiliary cavities 9 and 10 are arranged so as to be symmetric in the E plane which is a plane along the electric field of the radiated electromagnetic wave. The auxiliary cavities 9 and 10 are set so as to emit an electromagnetic wave having a phase opposite to that of the electromagnetic wave radiated from the main cavity 7. In this way, the primary radiator 200 is configured.

  As shown in FIG. 5, the reflecting mirror 3 having a rectangular mirror surface 4 is arranged so as to face the primary radiator opening of the primary radiator 200. The primary radiator 200 and the reflecting mirror 3 constitute a reflecting mirror antenna device 101.

  As shown in FIG. 4, since the cross section of the main cavity 7 has a square shape, the shape of the opening of the primary radiator is a shape close to a rectangle V surrounded by the line EFGH in the figure. The size of the main cavity 7 is set so that the amplitude distribution of the electromagnetic wave at the opening of the primary radiator becomes a distribution close to the distribution of the sinc function shown in FIG.

Next, with reference to FIGS. 4 and 5, the operation of the reflector antenna device 101 will be described focusing on the operation of the primary radiator 200.
The electromagnetic wave that has propagated through the conical horn 5 and reached the horn opening 6 is radiated from the main cavity 7 through the coupling portion 8. The electromagnetic wave that has reached the horn opening 6 is radiated from the auxiliary cavities 9 and 10 via the coupling portions 11 and 12. At this time, the auxiliary cavities 9 and 10 emit electromagnetic waves having a phase opposite to that of the electromagnetic waves radiated from the main cavity 7.

  Since the shape of the opening of the primary radiator is close to the rectangle V, the radiator opening distribution, which is the electromagnetic wave distribution of the primary radiator opening of the primary radiator 200, is a substantially rectangular distribution. The reflector aperture distribution, which is the distribution of electromagnetic waves on the mirror surface 4, also has a substantially rectangular distribution. Further, the auxiliary cavities 9 and 10 arranged symmetrically in the E plane emit electromagnetic waves having a phase opposite to that of the main cavity 7, so that unnecessary side lobes generated along the E plane can be suppressed.

  When the length L of the main cavity 7 is long, the electromagnetic wave mode is converted into a rectangular waveguide mode in the main cavity 7, and the radiator aperture distribution of the primary radiator 200 is the same as the aperture distribution of the pyramid horn. Distribution. On the other hand, when the length L is short, the radiator aperture distribution of the primary radiator 200 becomes the same distribution as the aperture distribution of the conical horn 5. On the other hand, in the primary radiator 200, the length L of the main cavity 7 is set to a length equivalent to a quarter wavelength of the radiated electromagnetic wave. As a result, the amplitude distribution of the electromagnetic wave at the opening of the primary radiator does not become the amplitude distribution of the opening of the cone horn or the pyramid horn, but the distribution of the sinc function shown in FIG.

  Furthermore, since the cross sections of the auxiliary cavities 9 and 10 are rectangular, the primary radiator 200 including the primary radiator opening can be easily manufactured.

  As described above, in the reflector antenna device 101 of the second embodiment, the primary radiator 200 has the conical horn 5 and the horn opening 6 is provided with the main cavity 7 having a square cross section. The size of the main cavity 7 is set so that the amplitude distribution of the electromagnetic wave at the opening of the primary radiator approaches the distribution of the sinc function shown in FIG. Thereby, the reflector opening distribution of the reflector 3 can be made into a rectangular uniform distribution, and spillover can be suppressed. As a result, the electromagnetic wave can be efficiently irradiated from the primary radiator 200 onto the rectangular mirror surface 4.

Embodiment 3 FIG.
With reference to FIG.6 and FIG.7, the reflective mirror antenna apparatus which provided the arcuate auxiliary | assistant cavity in the primary radiator is demonstrated. In addition, the same code | symbol is attached | subjected to the structural member similar to the reflector antenna apparatus 101 of Embodiment 2 shown in FIG.4 and FIG.5, and description is abbreviate | omitted.

  Adjacent to the side of the main cavity 7, two auxiliary cavities 9 a and 10 a having a circular arc cross section are provided. The auxiliary cavities 9 a and 10 a have hollow portions that communicate with the horn opening 6, and coupling portions 11 and 12 that are coupling holes that are electromagnetically coupled to the conical horn 5 are formed. The primary radiator opening is constituted by the main cavity 7 and the auxiliary cavities 9a and 10a.

  The two auxiliary cavities 9a and 10a are arranged symmetrically in the E plane, which is a plane along the electric field of the radiated electromagnetic wave. The auxiliary cavities 9a and 10a are set so as to emit an electromagnetic wave having a phase opposite to that of the electromagnetic wave emitted from the main cavity 7. In this way, the primary radiator 201 is configured.

  As shown in FIG. 7, the reflecting mirror 3 having a rectangular mirror surface 4 is disposed so as to face the primary radiator opening of the primary radiator 201. The primary radiator 201 and the reflecting mirror 3 constitute a reflecting mirror antenna device 102.

Primary radiator 201 operates as follows similarly to primary radiator 200 of the second embodiment.
That is, the electromagnetic wave that has propagated through the conical horn 5 and reached the horn opening 6 is radiated from the main cavity 7 through the coupling portion 8. The electromagnetic wave that has reached the horn opening 6 is radiated from the auxiliary cavities 9a and 10a via the coupling portions 11 and 12. At this time, the auxiliary cavities 9 a and 10 a radiate an electromagnetic wave having a phase opposite to that of the electromagnetic wave radiated from the main cavity 7.

  Since the cross sections of the auxiliary cavities 9a and 10a are arc-shaped, the amplitude distribution of the electromagnetic wave at the opening of the primary radiator becomes closer to the distribution of the sinc function shown in FIG. As a result, the reflector aperture distribution, which is the distribution of electromagnetic waves on the mirror surface 4 of the reflector 3, can be easily made into a rectangular uniform distribution, and spillover can be easily suppressed.

Embodiment 4 FIG.
With reference to FIGS. 8 and 9, a reflector antenna apparatus using a horn having an elliptical cross section (so-called “elliptic cone horn”) as a primary radiator will be described. In addition, the same code | symbol is attached | subjected to the structural member similar to the reflector antenna apparatus 101 of Embodiment 2 shown in FIG.4 and FIG.5, and description is abbreviate | omitted.

  In the figure, 5a is an elliptical cone horn. The horn opening 6 of the elliptical cone horn 5a is provided with a main cavity 7 having a square cross section. Two auxiliary cavities 9 and 10 are provided adjacent to the side of the main cavity 7. A primary radiator opening is constituted by the main cavity 7 and the auxiliary cavities 9 and 10. In this way, the primary radiator 202 is configured.

  As shown in FIG. 9, the reflecting mirror 3 having a rectangular mirror surface 4 is disposed so as to face the primary radiator opening of the primary radiator 202. The primary radiator 202 and the reflecting mirror 3 constitute a reflecting mirror antenna device 103.

Primary radiator 202 operates as follows similarly to primary radiator 200 of the second embodiment.
That is, the electromagnetic waves that have propagated through the elliptical cone horn 5 a and reached the horn opening 6 are radiated from the main cavity 7 through the coupling portion 8. The electromagnetic wave that has reached the horn opening 6 is radiated from the auxiliary cavities 9 and 10 via the coupling portions 11 and 12. At this time, the auxiliary cavities 9 and 10 emit electromagnetic waves having a phase opposite to that of the electromagnetic waves radiated from the main cavity 7.

  Since the elliptical cone horn 5a has an elliptical cross section, the beam width of the E surface, which is a surface along the electric field of the radiated electromagnetic wave, and the beam width of the H surface, which is a surface along the magnetic field, can be made uniform. Further, since the design parameters of the primary radiator 202 are increased, the electromagnetic wave amplitude distribution in the primary radiator opening can be made closer to the sinc function distribution shown in FIG.

  Instead of the square auxiliary cavities 9 and 10 shown in FIG. 8, arc-shaped auxiliary cavities 9a and 10a shown in FIG. 6 may be provided.

Embodiment 5. FIG.
A reflector antenna apparatus using a pyramid horn as a primary radiator will be described with reference to FIGS. 10 and 11. In addition, the same code | symbol is attached | subjected to the structural member similar to the reflector antenna apparatus 101 of Embodiment 2 shown in FIG.4 and FIG.5, and description is abbreviate | omitted.

  In the figure, 5b is a pyramid horn. A main cavity 7 having a square cross section is provided in the horn opening 6 of the pyramid horn 5b. Two auxiliary cavities 9 and 10 are provided adjacent to the side of the main cavity 7. A primary radiator opening is constituted by the main cavity 7 and the auxiliary cavities 9 and 10. In this way, the primary radiator 203 is configured.

  As shown in FIG. 11, the reflecting mirror 3 having a rectangular mirror surface 4 is arranged to face the primary radiator opening of the primary radiator 203. The primary radiator 203 and the reflecting mirror 3 constitute a reflecting mirror antenna device 104.

Primary radiator 203 operates as follows in the same manner as primary radiator 200 in the second embodiment.
That is, the electromagnetic wave that has propagated through the pyramid horn 5 b and reached the horn opening 6 is radiated from the main cavity 7 through the coupling portion 8. The electromagnetic wave that has reached the horn opening 6 is radiated from the auxiliary cavities 9 and 10 via the coupling portions 11 and 12. At this time, the auxiliary cavities 9 and 10 emit electromagnetic waves having a phase opposite to that of the electromagnetic waves radiated from the main cavity 7.

  At this time, the size of the main cavity 7 is set so that the amplitude distribution of the electromagnetic wave at the opening of the primary radiator approaches the distribution of the sinc function shown in FIG. Thereby, the reflector opening distribution of the reflector 3 can be made into a uniform rectangular distribution, and side lobes can be suppressed to suppress spillover. As a result, electromagnetic waves can be efficiently irradiated from the primary radiator 203 onto the rectangular mirror surface 4.

  Instead of the square auxiliary cavities 9 and 10 shown in FIG. 10, arcuate auxiliary cavities 9a and 10a shown in FIG. 6 may be provided.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Primary radiator, 2 opening part, 3 reflector, 4 mirror surface, 5 cone horn, 5a elliptical cone horn, 5b pyramid horn, 6 horn opening part, 7 main cavity (square cavity), 8 coupling part, 9, 9a, 10, 10a Auxiliary cavity, 11, 12 coupling part, 100, 101, 102, 103, 104 Reflector antenna device, 200, 201, 202, 203 Primary radiator.

Claims (7)

In a reflecting mirror antenna device comprising a mirror surface having a rectangular outer shape and a primary radiator disposed opposite to the mirror surface, and reflecting electromagnetic waves radiated from the primary radiator on the mirror surface,
The primary radiator is:
Install a square cavity in the opening of the inverted frustum-shaped horn,
Two auxiliary cavities are installed adjacent to the rectangular cavity so as to be symmetrical in a plane parallel to the electric field of the electromagnetic wave,
A coupling portion is formed between the rectangular cavity and the auxiliary cavity and the horn.
With that
Anti Ikyo antenna device you characterized in that setting the reflector opening distribution mirror as the electromagnetic wave of amplitude and phase on the mirror surface becomes uniform distribution radiator opening distribution of Fourier transform. Reflector antenna apparatus according to claim 1, characterized in that the shape of the auxiliary cavity in a square shape. Reflector antenna apparatus according to claim 1, characterized in that the shape of the auxiliary cavity in an arc shape. Reflection according to any one of claims 1 to 3, characterized in that the length of the rectangular cavity along the tube axis direction of the horn length of one-quarter wavelength of the electromagnetic wave Mirror antenna device. The horn reflector antenna device according to any one of claims 1 to 4, characterized in that configured in conical horn. The reflector antenna apparatus according to any one of claims 1 to 4 , wherein the horn is an elliptical cone horn. The reflector antenna device according to any one of claims 1 to 4 , wherein the horn is a pyramid horn.

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